1. Field of the Invention
The invention is concerned with filtering arrangements within hydraulic reservoirs and more particularly with an improved hydraulic reservoir using a particular filtering arrangement therewithin. Still more particularly the invention is concerned with particular means for holding filter elements within particular filter means which is located within a hydraulic reservoir.
2. Prior Art
The prior art as illustrated for example by the teachings of U.S. Pat. No. 3,685,658 generally teaches external spin or thread-on type filters which are mounted externally of hydraulic reservoirs and other apparatus. While such filters have advantages in many applications there are also a number of applications wherein it is more desirable to have the filter means within a hydraulic reservoir whereby dirty hydraulic fluid which is returned to the reservoir must pass through the filter means and thereby be cleaned and pass back into the reservoir from whence it may be pumped back to a hydraulic system. Some filter elements are also used within hydraulic reservoirs such as those disclosed in, for example, U.S. Pat. No. 3,886,072 and 3,900,400 but these are of considerably different structure, operation and mounting than are the structures of the present invention.
When one desires to replace filter means within a reservoir several problems are encountered which are not generally encountered with externally mounted filter means. For example, a particular problem which encountered is that adaquate means must be provided for fastening the elements of the filter means in place whereby generally all of the hydraulic fluid which enters the filter elements must pass through them before returning to the reservoir. Further, means must be provided which allow for the easy removal and replacement of the filter elements as they become dirtied. The present invention provides an improved hydraulic reservoir internal filter means improvement which has the aforementioned attributes. Other advantages of the improvement of the present invention will be apparent from reading the description which follows.